Stress-relieving articulation for prosthetic dentures



JOHNSON 6 m A 5 Pa w 6 2 an 2 m a w INVENTOR L EONA RD E. JOHNSON V ATTORNEY Patented Mar. 27, 1951 UNITED STATES PATENT OFFICE STRESS-RELIEVING ARTIGULATION FOR PROSTHETIC DENTURES Leonard E. J ohnson, Wheat Ridge, Colo.

Application October 2, 1948, Serial No. 52,446

'7 Claims.

This invention relates to the construction and production of prosthetic dentures, and more particularly to the construction and production of partial dental restorations for mounted association with and to complete an impaired set of natural teeth, and has as an object to provide an improved method for the production of and an improved construction for such restorations. A further object of the invention is to provide improved stress-minimizing means in interconacterized by an articulation permissive of pressure-reactive adjustment of the restoration relative to its anchor or mounting.

A further object of the invention is to provide an improved method for the production of stressminimizing dental restoration constructions applicable to a wide range of particular dental restorations pertaining to both upper and lower tooth sets, that is susceptible of development through the use of known and available materials common to such restorations, that is durable in use, comfortable to the wearer, and conservative of the natural teeth employed as anchors for the appliance. 7

With the foregoing and other objects in view,

-my invention consists in the construction, ar-

rangement, and combination of elements, and in the method employed for their construction and operative interrelation, as hereinafter set forth, pointed out in my claims and illustrated by the accompanying drawing, in which Figure 1 is a somewhat diagrammatic plan view of an appliance embodying the features of the invention as associated with and to partially complete an impaired set of natural teeth. Figure 2 is a fragmentary, detail elevation, partially in section and on an enlarged scale, of the construction according to Figure 1 as viewed from the indicated line 2-2 of said latter showing.

Figure 3 is a rear or inner end elevation of the appliance of Figure I removed from its mounted association. Figure 4 is a fragmentary, detail section, on an enlarged scale, vertically through the improved stress-minimizing coupling of the improvement. Figure 5 is a detail elevation, on

an enlarged scale, of a coupling plate element,-v

characteristic of the improvement. Figure .6 is a top plan view of the showing of Figure 5. Fige ure 7 is an elevation of the plate shown in Figure -5 as conditioned preparatory to its inclusion in a restoration through practice of the improved .method. Figure 8 is a side elevation of the show.- ing of Figure '7. V

A type of dental restoration commonly and extensively in use for the replacement .of lost molar teeth comprises a tooth equipped, saddle,-

llke, rigid member embracingly engageable over and to seat against the gum ridge area to be restored, anchoring means engageable with certain of the remaining natural teeth to mount and position said member, and an articulated coupling between said member and anchoring means. A characteristic shortcoming of restorations of the type above described is the opera.- tive inadequacy .of the articulated coupling conventionally employed; such couplings normally providing only a limited hingeproduction of undesirable stresses on the anchor tooth or teeth as well as ultimately painful concentration of operative pressures on the gum area embraced by the restorations, while the operating loads improved on the simple hinge-type coupling frequently result in distortion or failure -.of the latter. Another disadvantage of such conventional restoration constructions derives from the method of coupling manufacture .and assembly; it being usually necessary to separately fabricate the various small elements of the coupling and subsequently assemble them in a manner and through agencies productive of a delicate, structurallyweak joint subject to failure and difiicult of repair. Directed to the preservation of advantages inherent in restorative appliances 0f the character above discussed and to the elimination of the shortcomings and disadvantages above mentioned, the improvements hereinafter set forth provide an articulated coupling susceptible of cast production in operative form wherethrough the destructive effect of operative pressures is minimized, strains on the anchor teeth are largely obviated, and the replacement memher is floatingly accommodated in maintained bearing engagement over the-embraced In thedrawing, a typical restorative appliance is illustrated-as including .a rigid, suitably-coritoured, saddles-like member 15 equipped, in this instance, with three replacement molar teeth 16. The member I5 is formed from any suitable, initially-plastic material of the character noW employed for such purposes and is shaped and contoured in a Well-understood manner .to embra-- ingly engage over and seat smoothly against the gum ridge area to be furnished with the restoration. The substitute teeth I6 are of any acceptable conventional material and construction and are fixedly engaged in and with the material of the member I to project from the latter in simulation of natural tooth position when said member is in place on and in the desired relation with the gum ridge; all of the foregoing being known and usual practice in the art of prosthetic denture production.

To mount, support and operatively position the member I5 carrying the teeth I6, a clip-type frame I I, in this instance of modified yoke form adapted to lie inwardly adjacent the gum bearing the remaining natural teeth, is formed from suitable metal in a manner hereinafter to be described and to the particular shape and contour suited to a given restoration. Suitably spaced apart on the frame IT and preferably integral therewith, pronged clips I8 outstand from the plane of said frame and in the illustrated example adjacent the frame ends to embracingly engage with and clip over the natural teeth adjacent the position of the restoration, thereby removably and replaceably securing the frame I! in its position of desired use in accordance with conventional practice., The frame I1 of the improvement exhibits novelty in that it is split or divided longitudinally and inwardly from its end adjacent the restoration to provide an upper arm portion I9 carryin the associated clip I8 and an under arm portion 20 integrally merging with the arm I9 at same distance inwardly from the frame I! end and susceptible of resiliently-yieldable divergence from its associated arm I9 within the elastic limits of the material from which the arms are formed. The arm 20 of the frame I! is formed with an integral extension outwardly beyond the position of the adjacent clip I8 and laterally through the area to be occupied by the restoration, said extension conveniently being formed as a curved loop- 2I shaped to overlie the gum ridge whereupon the restoration is to be based. The loop 2| is the principal mounting and support for the member I5, said member being molded about and embedding said loop in accordance with wellknown practice to properly align the substitute teeth I6 with the remaining natural teeth, and

such mounting, of the member I5 on and in fixed relation with an extension of the arm 20 provides, through the resilient yieldability of said arm relative to the frame I1 and attaching clips I8, for a degree of play between the gum ridge and the coacting inner face of the member to the end that said member may adjust and align under imposed pressures for maintenance of comfortable, wide area, seated relation against the gum.

As will be obvious, the restoration mounting provided by the arm 20 and its loop extension 2I guishing characteristic of the invention. In accordance with the principles of the invention, an integral, thin web 22 is formed as a continuation of and rearwardly from the clip I8 above the arm 20, said web hence being rigidly associated with the arm I9, and the free rearward margin of said web is formed as a straight edge substantially perpendicular to the line of separation betweenthe arms I9 and 20 and closely, but spacedly. paralleling a straight forward edge of the member I5. The web 22 is thus disposed to project away from the natural tooth engaged by the associated clip I3 and into the zone of the restoration, the latter being formed to accommodate said web inwardly adjacent one of the tooth elements I6.

The web 22 is intersected by an opening of relatively substantial area and particular shape, said opening having a relatively greater height perpendicular to the line of separation between the arm portions I9 and 20, a relatively lesser width parallel to said line of separation, a straight margin limiting its height inwardly adjacent and substantially parallel to said line of separation, a concavely-arcuate margin limiting its height remote from said line of separation and hence adjacent the free outer margin of said web, and oppositely-inclined margins determining its width in a uniform divergence from mergence with the arcuate margin ends to maximum separation at their intersection with said straight margin. An arm 23 of an integral with the loop 2I is suitably curved and directed to emerge from the member I5 between the opposed faces of the web 22 and adjacent restoration tooth I6, and the end of said arm 23 engages through the opening in said web and is shouldered over the opening margins, all in a particular manner, to complete a slidablyanchored, brace link between said loop, and the restoration carried thereby, and the clip I8 employed to position and anchor the appliance. The end of the arm 23 engaged through the opening in the web 22 conforms closely to the outline determined by the arcuate end and divergent side walls thereof and is adapted to seat snugly thereagainst when the arm portions I9 and 20 are at a minimum of separation, thereby guiding and bracing the member I5 in its normal relation with the yoke I'I, clip I8, and web 22, but the margin of said arm 23 end adjacent the web opening straight margin opposed to the arcuate margin spacedly parallels said opening straight margin when the associated elements are normally interrelated and thereby provides for play of said engaged arm 23 end altitudinally of the web opening as the arm portions I9 and 20 are caused to separate, any unseating of the arm 23 end from its engagement against the web opening arcuate margin providing, by virtue of the divergent opening side margins, a limited degree of play perpendicular to the altitudinal range through which a self-seating rocking of the member I5 relative to the yoke IT and clip I8 may be accommodated, all without impairing the security afiorded by the brace arm 23 and with a minimum of stress transmitted through the clip I8 to the tooth embraced thereby. On each face of the web 22, the material forming the end of the arm 23 traversing the web opening is laterally expanded to form shoulders overlapping on said web about the arcuate end and divergent side margins of the web opening, a terminal button 24 thus marking said arm end on the inner surface of the appliance, but the space between the parallel, straight marginsof said arm end and web opening is uncovered on the appliance inner surface, thus obviating any permanent obstruction thereof.

While it is conceivable that various methods and agencies might be employed to the satisfactory development of the improvement hereinabove described, considerations of economy, practicability, precision, and durability emphasize the desirable importance of the techniques and procedures hereinafter set forth as particularly applicable to such development.

It-is accepted, customary practice to form the positioning, anchoring, and other stress-resistant,- rigid elements of prosthetic dentures, such adjustments, and a degree of softness and flexibility which restricts their usefulness inthin sections or attenuations, such as the web 22. Preserving the advantages of themetals normally employed for like purposes, the yoke l1, clips 18, arms l9 and 20, loop 2!, and arm 23 of the improvement are constituted therefrom, in the manner hereinafter set forth, while the web 22 is supplied in the form of a thin, prefabricated plate 25, of hard, rigid material, such as steel, partially embedded within and fused to the softer metal of the appliance to position the web opening as heretofore explained. The plate 25 is outlined as shown in Figure 5 with one rightangled corner whereof the straight, intersecting margins become the corresponding web 22 margins respectively perpendicular to and spacedly parallel with the line of separation between the arms is and 20, indented, or serrate margins opposed to said straight margins defining attaching fingers 26 whereof the ends are alternately oppositely bent to function as anchoring lugs, and an aperture having the characteristics of the opening previously described as intersecting the web 22, save that, in the plate 25, the straight margin of said opening opposed to the opening arcuate margin is extended at each end to intersection with the opening convergent side margins and beyond the latter to produce opposed notches 21 having like depths altitudinally of the plate equal to the amount of altitudinal play desired for the opening-engaged end of the arm 23 relative to the web 22.

Given a preformed plate 25 for the development of each web 22 desired in a given appliance, and such preformed yoke and clip elements as it may be desired to employ, the other metallic elements of the ultimate appliance are simulated in wax, as is customary practice, and the preformed metallic elements associated therewith in the relationships pertinent to the ultimate unit; the face areas of the plate 25 immediately surroundin the margins of the opening therethrough as well as said margins, being first coated, as at 28, with a mixture or compound effective to nullify adherence of the softer metal, at its lower temperature of fusion, to the body of said plate, and a preformed block 29, of heatresistant, frangible material, being engaged perpendicularly through said plate with its ends filling the notches 21 of the plate opening, the length of said block overlying the opening straight margin opposed to the openin arcuate margin, and the width of said block exceeding the plate thickness so as to project beyond each face thereof. The wax simulation of the arm 23 extending through the plate 25 opening from the loop 22 will be shouldered over the coated areas 28 of said plate and will close against one side and the exposed face of the block 29 carried by the plate, while the wax simulation of the metal joining the arm 29 and associated clip l8 will smoothly cover and embed the plate fingers 26 and close over uncoated areas of said plate to consolidate the latter in the pattern or model of the appliance. With the metallic elements and wax simulations of the device integrated in the desired assembly, theunit is enclosed in a plaster, or similar, mould, as is conventional practice, and the mould is provided with the requisite pouring gates and vents, so that the softer metal for completion of the appliance, in molten form, may be introduced through the gates to melt, dislodge, and replace the wax portions of the pattern and to unite, in

hardening incident to cooling, with the metallic elements of the pattern. When the mould is opened, the plate 25 will be found to be partially embedded in and firmly fused to the metal of associated portions of the arm l9 and clip [8, and the arm 23 will have been formed in filling engagement through the plate opening and shouldered relation over the coated areas 28 of the plate, the block 29 serving as a, spacer to hold the arm 23 metal away from the opening straight margin paralleling the line of separation between the arms l9 and 20. There being no metal covering the side of the block 29 on the inward side of the moulded device, said block may be readily broken up and removed with a fine pick, or similar tool, whereafter a slight tap on the shouldered end of the arm 23 in the direction of the line of separation between the arms is and 20 serves to disrupt any bonds that may have developed between the plate and the relativelyshiftable end of said arm and free the latter for play altitudinally of the plate within the limits permitted by its engagement through the plate opening, said plate 25 now being in effect and in fact the web, 22. Thus, the moulding operation forms and completes a stress-minimizing articulation having the functions and characteristics previously explained, all without the necessity for onerous machining and assembly of delicate parts and with no complication of normal procedures other than the provision and incorporation of the plate 25.

Completion of the restoration after the moulding of the metallic arts of the appliance is in accord with conventional practice, the saddle l5 and teeth [6 being associated with the loop 22 and arms 20 and 23 in a usual and customary manner.

Since many changes, variations, and modifications in the specific form, construction, and arrangement of the elements shown and described may be had without departing from the spirit of my invention, I wish to be understood as being limited solely by the scope of the appended claims rather than by any details of the illustrative showing and foregoing description.

I claim as my invention:

1. The combination with an operatively-rigid, clip-anchorable, denture yoke, of an integral yoke arm resiliently yieldable in opposition to an anchor clip, an integral, restoration-supporting extension of said arm projecting beyond said yoke, an apertured Web fixedly associated with said yoke adjacent the anchor clip opposed by said arm, an element of said extension shiftably traversing the aperture of said web, and shoulders on said element overlapping opposite faces of said web to inhibit displacement of said element longitudinally relative to the Web.

2. The combination as set forth in claim 1 wherein said web is disposed in substantially the plane of resilient yoke arm yieldability.

3. The combination as set forth in claim 1,

amass? wherein the web aperture is elongated perpendicular to the resilient yoke arm, has a concave end margin remote from said arm, a straight end margin adjacent said arm, and straight side margins diverging from tangency with said concave end margin to angular intersection with said straight end margin.

4. The combination as set forth in claim 1, wherein said web is constituted from a separate, hard metal plate preformed for fixed incorporation with said yoke in substantially the plane of resilient yoke arm yieldability.

5. The combination as set forth in claim 1, wherein said web is constituted from a separate, hard plate preformed for fixed incorporation with said yoke in substantially the plane of resilient yoke arm yieldability and with an elongated aperture defined by a concave end margin, an opposite, straight end margin, and straight side margins diverging from tangency with said concave end margin to angular intersection with said straight end margin.

6. The combination as set, forth in claim 1, wherein said web is disposed in substantially the plane of resilient yoke arm yieldability, the web aperture is elongated perpendicular to said yoke arm and characterized by a concave end margin remote from said arm, a straight end margin adjacent said arm, and straight side margins diverging from tangency with said concave end margin to angular intersection with said straight end margin, and said arm extension element portion traversing the web aperture is formed to conform with and normally close against the aperture concave end margin and adjacent aperture side margin reaches in a parallel spacing away from the aperture straight end margin, whereby pressure-responsive yielding of the resilient yoke arm is reflected as limited travel of 7. In a prosthetic denture having a clip-anchorable mounting yoke and an integral, restoration-supporting arm projecting from said yoke beyond an anchoring clip thereof, a stress-relieving articulation operatively between said yoke and restoration, comprising a cut separating otherwise integral portions of said arm and. yoke to render said arm resiliently yieldable relative to said yoke in opposition to the adjacent-anchoring clip, a web fixedly associated with said yoke adjacent said anchoring clip in substantially the plane of arm yieldability, an aperture intersecting said web elongated perpendicular to said arm, an arm element end-engaged through and shouldered over opposite faces of said web, and coacting web aperture margin and arm element conformations effective to provide wedged interengagement thereof in normal, non-stressed relations of said arm and yoke and to permit limited longitudinal and consequent lateral play of said element within said aperture when said arm is pressure-flexed relative to said yoke. LEONARD E. JOHNSON.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 1,746,037 Groove Feb. 4, 1930 2,279,351 Skinner Apr. 14, 1942 2,409,783 Moskey Oct. 22, 1946 

